i dont have the MiNewt but i made a similar lumen's upgrade from Luxeon (<100) to SSC P4 (150 lumens) on my Princeton Tec Apex headlamp . The P4 uses less power and produces more light with more flood. Is it worth $50? i dunno. I paid $5 for the LED and did the swap myself.
Im considering buying the MiNewt myself, and cant decide between the USB, X2, or Twin MiNewt.